Math AID! - 2-function questions

Question

 f(x)=9+x+x^2

The task is to:

1. Find f(x + h) and simplify.
2. Find f(x+h)-f(x)/h and simplify.

Answer 1

It's probably the most conenient way to solve it:

f(X) = X² + X +9

f(X+h) = ( x+h)² + (X + h) + 9

            =  X² + 2hx + h² + X +h +9

             = X² +(2h+1)X +h +9

[ f (X + h)- f (X)] /h = ( X² +2hx+X+h+9- X² -X - 9)/h =

                                         2hx+h/ h = 2x +1